Over the past nine years or so under Diego Simeone, Atletico Madrid had become that team "no one wants to play" in a knockout clash.
Their resilience, work ethic and downright dirtiness made them arguably the toughest team to play against in Europe – not because of any particular brilliance, but because they were the embodiment of their coach on the pitch.
That aura has somewhat diminished over the past 18 months or so, and there's no getting away from the fact this has been a testing season for Atletico and Simeone, with few giving them a chance against European champions Liverpool in the Champions League last 16.
After finally getting past the Antoine Griezmann saga in pre-season, there had been a feeling Atletico could hit the reset button and begin a process of reinvention following signs of stagnation.
They've done anything but. While they remain shrewd defensively, in attack Atletico are as toothless as they have ever been under Simeone, having only scored more than one other side in LaLiga's top 10.
An anxiousness seems to have engulfed Atletico at times this term, their new-look team appearing uneasy with the pressure that accompanies their established status as favourites in almost any match.
But on Tuesday they were transformed. For a night, the real Atletico were back, and they beat Liverpool 1-0 at the Wanda Metropolitano.
Their start was as good as anything Atletico have produced all season. Whether they were spurred on by the raucous atmosphere inside the Wanda or some feisty pre-match words from Simeone, it's unclear.
However, Atletico were sharper than the European champions everywhere, snapping into tackles, getting the ball forward quickly and directly, and their intensity off the ball was like the classic Atleti sides of the previous decade.
Atletico used to be the ultimate underdog, their tirelessness, tenacity and voracious nature mirroring the ideals and mannerisms of Simeone, who prowled the touchline throughout. They were never afraid of the big occasion, and all that came flooding back even when Liverpool were on the front foot.
A fortuitous touch off Fabinho allowed Saul Niguez to put Atletico in front after just four minutes.
An early goal from a corner, allowing them to absorb pressure and play on the counter or wait for errors – it was about as quintessential Atletico as it gets.
This situation should've seen them get a second goal in the 26th minute, as Virgil van Dijk's woeful defensive header was pounced on by Alvaro Morata, but after cutting inside Fabinho he could only shoot straight at Alisson from close range.
Liverpool were short of ideas in response, their first shot coming in the 29th minute – a rather hopeless long-range effort from the right foot of Andy Robertson, and Fabinho followed suit with a similarly harmless attempt soon after.
A Mohamed Salah shot that was crucially blocked by Felipe was the best the Reds could muster in the first half, and they fared little better after the interval and ended without a single shot on target, with Atleti's back four and hard-working front six doing a commendable job of limiting space for Liverpool to exploit.
"The people of Atletico always wanted a competitive team, a team that was strong in defence, a team that would play on the counter-attack and be a nuisance for the super-powerful sides," Simeone once wrote in the Coaches' Voice. They certainly delivered on that against Liverpool, with Atletico's coach spending virtually the entire match on his feet, playing the role of chief cheerleader.
Another opportunity fell to Morata on the break deep into the second half, but the much-maligned striker lost his footing at the crucial moment and he was withdrawn soon after.
And therein lies Atletico's biggest problem – with just seven goals, Morata is their most prolific scorer in LaLiga this season and there's every chance Liverpool will make him pay for wasting his two glorious opportunities when they resume hostilities at Anfield.
But on a night that Atletico once again reminded Europe of their status as masters of the mundane, Morata shouldn't be the focus.
No, at a time when many have suggested change is needed at the Wanda Metropolitano, Simeone showed evidence his dynasty's destructive powers are still capable of upsetting the elite.